A. Field of the Invention
This invention relates to the field of art of hydraulically actuated cutting and punching.
B. Prior Art
Large industrial size presses are known which both cut and punch structural members such as cable tray channels and rungs. Cable trays are used for supporting electrical cables and control circuits in applications such as nuclear plants, electrical generating plants and other industrial plants. Cable trays comprise two opposing channels with support members or rungs disposed at predetermined intervals between the channels. In practice, cable trays are usually cut and punched in the field at the site of the generating plant where the cable trays are actually being installed. It is only at the time of field installation that the exact lengths of cable tray sections are known. Large industrial sized nonportable presses for cutting and punching the cable trays are not suitable for use in the field and therefore, the cutting and punching operations have been performed manually by saw and drill. While portable punches have been known to punch one or more holes in metal structural members, punches have left much to be desired in combining both cutting and punching as well as providing a rigid support structure. The rigidity of the support structure for the hydraulic cylinder and for the cutting and punching operation is a critical problem since a portable punch must be greatly reduced in size and weight. Further, the entire assembly must have a simple means to allow for the entrance of the work piece or cable tray. Without a rigid support structure, prior assemblies have not precisly maintained cutting and punching alignment resulting in undesirable shearing, thereby causing unacceptable burrs as well as other problems.